Stability of Rivaroxaban and Apixaban Anti-Xa Activities in Whole Blood Samples: A French Bicentric Study.

Abstract

Over the last 10 years, the use of direct oral anticoagulants (DOACs) in the management of venous thromboembolism and atrial fibrillation grew significantly, and in particular direct factor Xa inhibitors rivaroxaban and apixaban. Clinical trials of these molecules did not underline the necessity of systematic laboratory monitoring, and the measurement of anti-Xa activity was only indicated in urgent situations such as trauma or prior to acute surgery.[1] [2] [3] [4] However, in 2021, the International Council for Standardization in Haematology (ICSH) updated these recommendations and added several nonurgent indications for anti-Xa activity measurement: advanced age, severe renal failure, ahead of a surgical procedure at high bleeding risk, body mass index >40 kg/m2, and drug interactions.[5] [6] The 2018 ICSH recommendations stated that citrated whole blood samples for anti-Xa activity measurement should be processed within 4 hours of collection, but without providing evidence. Moreover, the French Working Group on Hemostasis and Thrombosis recommendations indicated a shorter stability, of 2 hours, in accordance with the only study then published in the literature.[7] [8] [9] In practice, some laboratories may find it difficult to comply with these short delays.